1. Field of the Invention
The present invention relates to a driver assistance system for monitoring driving safety, having a mobile electronic unit including a video sensor, a computer unit for image data processing and an acoustic output unit, which detects the immediate surroundings of the vehicle from the data of the video sensor and outputs a warning or information via an output unit when the computer unit detects a hazardous situation, and to a corresponding method for detecting and evaluating a vehicle movement.
2. Description of Related Art
For active support of the driver of a vehicle in various traffic situations, there are known automatic driver assistance systems which provide the driver with useful information in navigating through the road traffic. In addition, published German patent document DE 199 82 422 and published European patent document EP 1826736 A1 describe systems for recognizing road signs, helping the driver to maneuver safely in complicated traffic situations. In addition to the known navigation systems, which display satellite-supported navigation data, there are known driver assistance systems, which help the driver in staying in his lane by acoustic signals and therefore give the driver warnings, for example, to detect fatigue and thereby prevent accidents. Since such systems are usually expensive and are mostly used only in new vehicles, it is proposed in published German patent document DE 10 2005 049 881 A1 that these systems be replaced by cellular telephones, most of which at the time of this patent application have an efficient camera with an equally efficient computer unit for processing the camera images. According to the last-cited document, the lane recognition function should be introduced into a cellular telephone via software, so that the cellular telephone which is positioned in a mounting cradle on the dashboard outputs a warning tone via the ringtone function of the cellular telephone when the approach to a lane change is detected. Due to the high reflectivity of most road markings, detection of a lane change is possible with a relatively high reliability, because the high contrast created due to the strong reflection supports automatic recognition of the road marking in the image data.
However, one disadvantage of the method cited above is a very one-sided and undifferentiated recognition of a lane change, resulting in frequent and unnecessary alarms. This may result in the driver deactivating the system or simply ignoring it due to the large number of warnings delivered unnecessarily.